// This file is part of Eigen, a lightweight C++ template library
// for linear algebra.
//
// Copyright (C) 2009 Benoit Jacob <jacob.benoit.1@gmail.com>
//
// This Source Code Form is subject to the terms of the Mozilla
// Public License v. 2.0. If a copy of the MPL was not distributed
// with this file, You can obtain one at http://mozilla.org/MPL/2.0/.

#include "main.h"
#include <Eigen/LU>
#include <algorithm>

template<typename MatrixType>
void
inverse_permutation_4x4()
{
	typedef typename MatrixType::Scalar Scalar;
	Vector4i indices(0, 1, 2, 3);
	for (int i = 0; i < 24; ++i) {
		MatrixType m = PermutationMatrix<4>(indices);
		MatrixType inv = m.inverse();
		double error = double((m * inv - MatrixType::Identity()).norm() / NumTraits<Scalar>::epsilon());
		EIGEN_DEBUG_VAR(error)
		VERIFY(error == 0.0);
		std::next_permutation(indices.data(), indices.data() + 4);
	}
}

template<typename MatrixType>
void
inverse_general_4x4(int repeat)
{
	using std::abs;
	typedef typename MatrixType::Scalar Scalar;
	double error_sum = 0., error_max = 0.;
	for (int i = 0; i < repeat; ++i) {
		MatrixType m;
		bool is_invertible;
		do {
			m = MatrixType::Random();
			is_invertible = Eigen::FullPivLU<MatrixType>(m).isInvertible();
		} while (!is_invertible);
		MatrixType inv = m.inverse();
		double error = double((m * inv - MatrixType::Identity()).norm());
		error_sum += error;
		error_max = (std::max)(error_max, error);
	}
	std::cerr << "inverse_general_4x4, Scalar = " << type_name<Scalar>() << std::endl;
	double error_avg = error_sum / repeat;
	EIGEN_DEBUG_VAR(error_avg);
	EIGEN_DEBUG_VAR(error_max);
	// FIXME that 1.25 used to be a 1.0 until the NumTraits changes on 28 April 2010, what's going wrong??
	// FIXME that 1.25 used to be 1.2 until we tested gcc 4.1 on 30 June 2010 and got 1.21.
	VERIFY(error_avg < (NumTraits<Scalar>::IsComplex ? 8.0 : 1.25));
	VERIFY(error_max < (NumTraits<Scalar>::IsComplex ? 64.0 : 20.0));

	{
		int s = 5; // internal::random<int>(4,10);
		int i = 0; // internal::random<int>(0,s-4);
		int j = 0; // internal::random<int>(0,s-4);
		Matrix<Scalar, 5, 5> mat(s, s);
		mat.setRandom();
		MatrixType submat = mat.template block<4, 4>(i, j);
		MatrixType mat_inv = mat.template block<4, 4>(i, j).inverse();
		VERIFY_IS_APPROX(mat_inv, submat.inverse());
		mat.template block<4, 4>(i, j) = submat.inverse();
		VERIFY_IS_APPROX(mat_inv, (mat.template block<4, 4>(i, j)));
	}
}

EIGEN_DECLARE_TEST(prec_inverse_4x4)
{
	CALL_SUBTEST_1((inverse_permutation_4x4<Matrix4f>()));
	CALL_SUBTEST_1((inverse_general_4x4<Matrix4f>(200000 * g_repeat)));
	CALL_SUBTEST_1((inverse_general_4x4<Matrix<float, 4, 4, RowMajor>>(200000 * g_repeat)));

	CALL_SUBTEST_2((inverse_permutation_4x4<Matrix<double, 4, 4, RowMajor>>()));
	CALL_SUBTEST_2((inverse_general_4x4<Matrix<double, 4, 4, ColMajor>>(200000 * g_repeat)));
	CALL_SUBTEST_2((inverse_general_4x4<Matrix<double, 4, 4, RowMajor>>(200000 * g_repeat)));

	CALL_SUBTEST_3((inverse_permutation_4x4<Matrix4cf>()));
	CALL_SUBTEST_3((inverse_general_4x4<Matrix4cf>(50000 * g_repeat)));
}
